• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 30
  • 22
  • 13
  • 5
  • 5
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 94
  • 25
  • 21
  • 16
  • 13
  • 12
  • 12
  • 11
  • 10
  • 10
  • 9
  • 7
  • 7
  • 7
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Ingénierie des applications Web : réduire la complexité sans diminuer le contrôle / Web applications engineering : reduce the complexity without loosing control

Richard-Foy, Julien 09 December 2014 (has links)
L'automatisation de certaines tâches et traitements d'information grâce aux outils numériques permet de réaliser des économies considérables sur nos activités. Le Web est une plateforme propice à la mise en place de tels outils : ceux-ci sont hébergés par des serveurs, qui centralisent les informations et coordonnent les utilisateurs, et ces derniers accèdent aux outils depuis leurs terminaux clients (ordinateur, téléphone, tablette, etc.) en utilisant un navigateur Web, sans étape d'installation. La réalisation de ces applications Web présente des difficultés pour les développeurs. La principale difficulté vient de la distance entre les postes client et serveur. D'une part, la distance physique (ou distance matérielle ) entre les machines nécessite qu'une connexion réseau soit toujours établie entre elles pour que l'application fonctionne correctement. Cela pose plusieurs problèmes : comment gérer les problèmes de latence lors des échanges d'information ? Comment assurer une qualité de service même lorsque la connexion réseau est interrompue ? Comment choisir quelle part de l'application s'exécute sur le client et quelle part s'exécute sur le serveur ? Comment éviter aux développeurs d'avoir à résoudre ces problèmes sans pour autant masquer la nature distribuée des applications Web et au risque de perdre les avantages de ces architectures ? D'autre part, l'environnement d'exécution est différent entre les clients et serveurs, produisant une distance logicielle. En effet, côté client, le programme s'exécute dans un navigateur Web dont l'interface de programmation (API) permet de réagir aux actions de l'utilisateur et de mettre à jour le document affiché. De l'autre côté, c'est un serveur Web qui traite les requêtes des clients selon le protocole HTTP. Certains aspects d'une application Web peuvent être communs aux parties client et serveur, par exemple la construction de morceaux de pages Web, la validation de données saisies dans les formulaires, la navigation ou même certains calculs métier. Cependant, comme les API des environnements client et serveur sont différentes, comment mutualiser ces aspects tout en bénéficiant des mêmes performances d'exécution qu'en utilisant les API natives ? De même, comment conserver la possibilité de tirer parti des spécificités de chaque environnement ? Les travaux de cette thèse ont pour but de raccourcir cette distance, tant logicielle que matérielle, tout en préservant la capacité à tirer parti de cette distance, c'est-à-dire en donnant autant de contrôle aux développeurs. / Thanks to information technologies, some tasks or information process can be automated, thus saving a significant amount of money. The web platform brings numerous of such digital tools. These are hosted on web servers that centralize information and coordinate users, which can use the tools from several kinds of devices (desktop computer, laptop, smartphone, etc.), by using a web browser, without installing anything. Nevertheless, developing such web applications is challenging. The difficulty mainly comes from the distance between client and server devices. First, the physical distance between these machines requires them to be networked. This raises several issues. How to manage latency ? How to provide a good quality of service even when the network is down ? How to choose on which side (client or server) to execute a computation ? How to free developers from addressing these problems without yet hiding the distributed nature of web application so that they can still benefit from their advantages ? Second, the execution environment is different between clients and servers. Indeed, on client-side the program is executed within a web browser whose API provides means of reacting to user actions and of updating the page. On server-side, the program is executed on a web server that processes HTTP requests. Some aspects of web applications can be shared between client and server sides (e.g. content display, form validation, navigation, or even some business computations). However, the APIs and environments are different between clients and servers, so how to share the same code while keeping the same execution performance as with native APIs ? How to keep the opportunity to leverage the specificities of a given platform ? This work aims at shortening this distance while keeping the opportunity to leverage it, that is while giving developers as much expressive power.
22

Effect of Maternal Melatonin Levels during Late Gestation on the Programming and Metabolic Disposition of Adipose Tissue and Skeletal Muscle in Bovine Offspring

Thompson, Robyn Carl 10 August 2018 (has links)
The objectives of this study were to determine: the effects of maternal melatonin (MEL) supplementation during late gestation on the histological and molecular regulation in the Longissimus dorsi (LM) muscle of fetal bovine offspring, composition and gene expression of fetal perirenal (PR) adipose tissue, and LM gene expression in postnatal offspring at birth and d 195 of age. Maternal supplementation of MEL during late gestation resulted in no difference in calf fetal body weight or birth weight. However, at d 195 of age, calves from MEL treated dams had an average body weight increase of 20 kg. Fetal LM weight and length tended to be increased in calves from MEL treated dams. Fetal gene expression of calves from MEL treated dams resulted in: increased LM adenosine monophosphate-activated protein kinase-α (AMPK) and decreased PR adiponectin (ADIPOQ), CCAAT enhancer binding protein alpha (CEBPA), proliferator activated receptor gamma (PPARg), and stearoyl-CoA desaturase (SCD). The improved metabolic status of LM coupled with the decrease in adipogenic gene expression, could result in calves from MEL treated dams having improved lean muscle accretion and reduced overall adiposity during postnatal development.
23

Studies on the economic efficiency of Kansas farms

Lopez Andreu, Monica January 1900 (has links)
Doctor of Philosophy / Department of Agricultural Economics / Jeffrey M. Peterson / This study focused on the economic efficiency of Kansas farms. The goal was to investigate factors and how they might affect farms and their economic and production performance. Kansas was selected as the region of study for its large agricultural production and distinctive type of multiple-operation farms. Farms in the sample could produce three outputs, crops, livestock and custom work. Inputs for the farms included measures of capital, labor, land and purchased inputs. Production outputs were measured in bushels and tons; input quantities were computed from input expenditures applying an input price index taken from the US Department of Agriculture in real US dollars. The dataset consisted of a 10-year (1998-2007) panel of 456 multi-output farms belonging to the Kansas Farm Management Association (KFMA). Data Envelopment Analysis (DEA) techniques were used to construct a non-parametric efficiency frontier and calculate technical efficiency (TE), allocative efficiency (AE), scale efficiency (SE), and overall or economic efficiency (OE) for each farm and each year. A discretionary input oriented DEA technique was used to assess the effect of capital availability as a farm input and its impact on farms' efficiencies. Efficiency scores in this problem were compared to the farms' scores when the level of debt was accounted for as a farm input. Panel data Tobit analysis was applied to the farms' inefficiency scores to investigate the causality of selected farm characteristics on technical, allocative, scale and overall inefficiencies. For the sampled farms and period, results confirmed that larger farms were more efficient than smaller ones. Farms specializing in livestock products, such as dairy and beef, were reported to be slightly more overall efficient than crop or mixed farms. Some economies of scope were found between custom work operations and crops. Financial structure of the farms was measured using the ratio of total debt to total assets for each farm. According to the results, larger leverage ratios increased all farm efficiencies. The positive effect of debt or capital availability in Kansas farms efficiencies was confirmed. The results of the technical efficiency discretionary DEA model agreed with this finding.
24

Search for the R(3520) crypto-exotic state at BABAR

Sherwood, Daniel January 2008 (has links)
Motivated by the recent discoveries of exotic and possible crypto-exotic states, presented in this thesis is an inclusive search for the production of a crypto-exotic baryon state called R(3520) with hidden charm in e+e− interactions at a centre of mass energy of 10.58 GeV in the data collected at the energy Υ(4S) resonance with the BABAR detector using a data set of 228 fb−1. Hints about the existence of the R(3520) state were reported in an analysis of data from a 2m hydrogen bubble chamber experiment at CERN. Two decay modes of the R(3520) resonance were investigated in this thesis R(3520) → pK+π−π−K0 S and R(3520) → pK+π−K∗−. The invariant mass spectra of the two final states were analysed and no evidence for the state was observed. Therefore, Upper limits were set on the differential cross section for the production of the R(3520) as a function of the momentum in the centre of mass frame. Using these differential cross sections the total cross sections were calculated with two different hypotheses for the width of the resonance, 1MeV/c2 and 7MeV/c2, with the additional assumption that the momentum spectrum for the production of state is flat. The upper limits for the total cross section production of the R(3520) for the decay mode p π− π− K+ K0 S were calculated to be 32 fb/GeV/c (48 fb GeV/c) with the 1MeV/c2 (7 MeV/c2) width. For the decay mode p π− K+ K∗− the upper limits on the total cross section were 62 fb/ GeV/c (93 fb/ GeV/c) for the 1MeV/c2 (7 MeV/c2) width hypotheses. The studies were repeated with the additional requirement that there was an additional antiproton in the event. The invariant mass spectra were analysed and no evidence for the state was found. Therefore, upper limits were calculated on the differential cross sections and the total cross sections for the production of this state. The upper limits for the total cross section production of the R(3520) for the decay mode p π− π− K+ K0 S were calculated to be 25 fb/GeV (36 fb/ GeV) with the 1 MeV/c2 (7 MeV/c2) width. For the decay mode p π− K+ K∗− the upper limits on the total cross section were 62 fb/GeV/c (83 fb/ GeV/c) for the 1MeV/c2 (7 MeV/c2) width hypotheses. This shows that the nonobservance of the state was unaffected by the condition that the baryon number was conserved in the event. The thesis also investigates the feasibility of using a new evolutionary algorithm, Gene Expression Programming, for an event selection problem relevant for the physics analysis presented here. The new methods allowed automatic identification of selection criteria similar to those based on cuts applied on event variables. This showed the feasibility of the new method.
25

Balanceamento de linhas de produção com trabalhadores deficientes e máquinas paralelas / Balancing assembly lines with disabled workers and parallel workstations

Araújo, Felipe Francisco Bezerra 03 May 2011 (has links)
O problema de balanceamento de linhas de produção e designação de trabalhadores (ALWABP, do inglês Assembly Line Worker Assignment and Balancing Problem ) é uma extensão do problema simples de balanceamento de linhas na qual os tempos de execução de tarefas são dependentes dos trabalhadores. Este problema tem sua motivação prática oriunda de linhas de produção com trabalhadores deficientes. Neste trabalho, focamos em uma extensão para o problema que permite lidar com a possibilidade de layouts de linhas com estações em paralelo. Além disso, estudamos uma segunda variante do problema que permite que os trabalhadores colaborem uns com os outros em uma mesma estação. Apresentamos formulações matemáticas para ambas as versões do problema. Adicionalmente, a partir de adaptações de métodos existentes para o ALWABP serial, desenvolvemos heurísticas construtivas para o ALWABP paralelo e ALWABP colaborativo. Testes computacionais em instâncias da literatura e uma análise detalhada dos resultados são apresentados / The assembly line and worker assignment balancing problem is an extension of the classical simple assembly line balancing problem where task execution times are workerdependent. This problem is motivated by the situation faced when balancing assembly lines with disabled workers. In this study, we focus on an extension for the problem with the goal of including the possibility of having layouts with parallel workstations. We also study a second variation for this problem that allows workers collaborating with each other. We present mathematical formulations for both problems. Moreover, constructive heuristics are developed, based on heuristic methods for the serial assembly line worker assignment and balancing problem. Computational tests on literature instances and a detailed analysis of the results are reported
26

Transformation de programmes logiques : application à la personnalisation et à la personnification d’agents. / Transformation of logic programs : application to personalization and personification of agents

Dubus, Georges 04 September 2014 (has links)
Cette thèse s'intéresse à la personnalisation et à la personnification d'agents intelligents dans le cadre d'applications web. Les techniques de personnalisation et de personnification sont de plus en plusutilisées pour mieux répondre aux besoins des utilisateurs. La plupart de ces techniques reposent sur des outils de raisonnement issus de l'intelligence artificielle. Cependant, ces techniques sont habituellement utilisés de manière ad-hoc pour chaque application. L'approche de cette thèse est de considérer la personnalisation et la personnification comme deux instances d'altération de comportement, et à étudier l'altération du comportements d'agents rationnels. Les principales contributions sont WAIG, un formalisme basé sur le langage Golog adapté à l'expression d'applications web, et PAGE, un cadre formel pour la manipulation et l'altération de programmes agents Golog, permettant la transformation automatique d'agent selon un critère donné. Ces contributions sont illustrés par plusieurs scénarios concrets issus des domaines de la personnalisation et de la personnification. / This thesis deals with personalization and personification of rational agents within the framework of web applications. Personalization and personification techniques are more and more used to answer the needs of users. Most of those techniques are based on reasoning tools that come from the artificial inteligence field. However, those techniques are usually used in an ad-hoc way for each application. The approach of this thesis is to consider personaliaation and personification as two instances of alteration of behaviour, and to study the alteration of the behaviours of rational agents. The main contributions are WAIG, a formalism for the expression of web applications based on the agent programming language Golog, and PAGE, a formal framework for the manipulation and the alteration of Golog agent programs, which allow to transform an agent automatically following a given criterion. Those contributions are illustrated by concrete scenarios from the fields of personalization and personification.
27

Model Predictive Control for Active Magnetic Bearings

Lundh, Joachim January 2012 (has links)
This thesis discuss the possibility to position control a rotor levitated with active magnetic bearings. The controller type considered is model predictive control which is an online strategy that solves an optimization problem in every sample, making the model predictive controller computation-intense. Since the sampling time must be short to capture the dynamics of the rotor, very little time is left for the controller to perform the optimization. Different quadratic programming strategies are investigated to see if the problem can be solved in realtime. Additionally, the impact of the choices of prediction horizon, control horizon and terminal cost is discussed. Simulations showing the characteristics of these choises are made and the result is shown. / Det här examensarbetet diskuterar möjligheten att positionsreglera en rotor som leviteras på aktiva magnetlager. Reglerstrategin som används är modellbaserad prediktionsreglering vilket är en online-metod där ett optimeringsproblem löses i varje sampel. Detta gör att regulatorn blir mycket beräkningskrävande. Samplingstiden för systemet är mycket kort för att fånga dynamiken hos rotorn. Det betyder att regulatorn inte ges mycket tid att lösa optimeringsproblemet. Olika metoder för att lösa QP-problem betraktas för att se om det är möjligt att köra regulatorn i realtid. Dessutom diskuteras hur valet av prediktionshorisont, reglerhorisont och straff på sluttillståndet påverkar regleringen. Simuleringar som visar karakteristiken av dessa val har utförts.
28

A Hybrid Neural Network- Mathematical Programming Approach to Design an Air Quality Monitoring Network for an Industrial Complex

Al-Adwani, Suad January 2007 (has links)
Air pollution sampling site selection is one of the most important and yet most vexing of the problems faced by those responsible for regional and urban air quality management and for the attainment and maintenance of national ambient air quality standards. Since one cannot hope to monitor air quality at all locations at all times, selection of sites to give a reliable and realistic picture of air quality becomes a major issue and at the same time a difficult task. The location (configuration) and the number of stations may be based on many factors, some of which may depend on limited resources, federal and state regulations and local conditions. The combination of these factors has made air quality surveys more complex; requiring comprehensive planning to ensure that the prescribed objectives can be attained in the shortest possible time and at the least cost. Furthermore, the choice and siting of the measuring network represents a factor of significant economic relevance for policymakers. In view of the fact that equipment, maintenance and operating personnel costs are increasing dramatically, the possibility of optimizing the monitoring design, is most attractive to the directors of air quality management programs. In this work a methodology that is able to design an optimal air quality monitoring network (AQMN) is described. The objective of the optimization is to provide maximum information about the presence and level of atmospheric contaminants in a given area and with a limited budget. A criterion for assessing the allocation of monitoring stations is developed by applying a utility function that can describe the spatial coverage of the network and its ability to detect violations of standards for multiple pollutants. A mathematical model based on the Multiple Cell Approach (MCA) was used to create monthly spatial distributions for the concentrations of the pollutants emitted from different emission sources. This data was used to train artificial neural networks (ANN) that were proven to be able to predict very well the pattern and violation scores at different potential locations. These neural networks were embedded within a mathematical programming model whose objective is to determine the best monitoring locations for a given budget. This resulted in a nonlinear program (NLP). The proposed model is applied to a network of existing refinery stacks and the locations of monitoring stations and their area coverage percentage are obtained.
29

A Hybrid Neural Network- Mathematical Programming Approach to Design an Air Quality Monitoring Network for an Industrial Complex

Al-Adwani, Suad January 2007 (has links)
Air pollution sampling site selection is one of the most important and yet most vexing of the problems faced by those responsible for regional and urban air quality management and for the attainment and maintenance of national ambient air quality standards. Since one cannot hope to monitor air quality at all locations at all times, selection of sites to give a reliable and realistic picture of air quality becomes a major issue and at the same time a difficult task. The location (configuration) and the number of stations may be based on many factors, some of which may depend on limited resources, federal and state regulations and local conditions. The combination of these factors has made air quality surveys more complex; requiring comprehensive planning to ensure that the prescribed objectives can be attained in the shortest possible time and at the least cost. Furthermore, the choice and siting of the measuring network represents a factor of significant economic relevance for policymakers. In view of the fact that equipment, maintenance and operating personnel costs are increasing dramatically, the possibility of optimizing the monitoring design, is most attractive to the directors of air quality management programs. In this work a methodology that is able to design an optimal air quality monitoring network (AQMN) is described. The objective of the optimization is to provide maximum information about the presence and level of atmospheric contaminants in a given area and with a limited budget. A criterion for assessing the allocation of monitoring stations is developed by applying a utility function that can describe the spatial coverage of the network and its ability to detect violations of standards for multiple pollutants. A mathematical model based on the Multiple Cell Approach (MCA) was used to create monthly spatial distributions for the concentrations of the pollutants emitted from different emission sources. This data was used to train artificial neural networks (ANN) that were proven to be able to predict very well the pattern and violation scores at different potential locations. These neural networks were embedded within a mathematical programming model whose objective is to determine the best monitoring locations for a given budget. This resulted in a nonlinear program (NLP). The proposed model is applied to a network of existing refinery stacks and the locations of monitoring stations and their area coverage percentage are obtained.
30

Design of a hyper-environment for tracing object-oriented requirements

Pinheiro, Francisco de Assis Cartaxo January 1997 (has links)
Change is inevitable and unending in developing large, complex systems. Changes to requirements arise not only from changes in the social context of the system, but also from improved understanding of constraints and tradeoffs as system development proceeds. How to trace software requirements is the problem addressed by this thesis. We present a solution for requirements tracing in the context of object-oriented software development. Our solution consists of a traceability model and a tool to automate the tracing. TOOR, the tool to implement the model, uses a project specification written in FOOPS, a general purpose object-oriented language with specification capabilities, to set up the environment in which a project is carried out. The project specification defines the trace units and traces as objects and relations, respectively. The evolution of objects from requirements sources to requirements to design to code, and generally to any object taking part in the process is dealt with in a uniform way in TOOR: classes are declared for each kind of object we wish to control, and relations are defined between them. TOOR uses regular expressions to provide a selective tracing mode: the actual configuration of objects and relations is considered as a text and regular expressions are used to retrieve parts of the configuration matching the pattern described by them. TOOR enhances the flexibility of regular expressions by extending the pattern matching procedure by providing different ways of specifying how an object or relation is to be matched. Other modes of tracing in TOOR are the interactive tracing through modules and the non-guided tracing through several browsing mechanisms. TOOR modules are used to structure projects by providing hierarchical scopes for objects used in a project development. The tracing mechanisms of TOOR can use the project structure to order searches or to provide boundaries for searching. Browsing objects provides additional flexibility in situations where little information of what has to be traced is possessed and hyper-media features address the need to re-interpret data usually encoded in different formats. The user-definable features of a project specification provides much of the flexibility necessary for effective use of a software tracing tool. Also, the integration of regular expression tracing with other forms of tracing such as browsing and interactive tracing makes TOOK an extremely versatile tool. The user can select the more appropriate form of tracing depending on context and can switch from one form to another as convenient.

Page generated in 0.0857 seconds